To a given straight line to apply a parallelogram equal to a given rectilineal figure and deficient by a parallelogrammic figure similar to a given one : thus the given rectilineal figure must not be greater than the parallelogram described on the half of the straight line and similar to the defect.
Secundum datam rectam data rectilineo equale parallilogrammum constituere deficiens flgura parallilogramma simili data. Oportet ergo datum rectilineum cui oportet equale constituere non maius esse eo quod a medietate describitur similibus existentibus defectionibus et ei quod a medietate et cui oportet simile deficere.